In the present study, Dr. A. H Nassar and colleagues sought to settle this issue by examining the stretch marks that arose in 210 pregnant women who were randomly assigned to apply cocoa butter or inactive “placebo” to their abdomen, breasts, and thighs once daily starting during the first trimester of pregnancy.

The study revealed that 45 percent of the cocoa butter using women devolped stretch marks compared to 49 percent who used a placebo. From a statistical standpoint this small difference is not considered significant.

Additionally there was no difference in the severity of stretch marks.

Their conclusion:

Our findings do not support the use of cocoa butter lotion for the prevention of striae gravidarum,” Nassar and colleagues conclude. Further studies, they say, are needed to confirm their findings in other populations and to evaluate the effectiveness of other commonly used products in preventing stretch marks.